Tobacco



I l r b w J '1 e ec r dt r iv those. obtainable by' .the of ammoniacalhy- Patented Dec. 1941 PATENT OFFICE r it I ItalphBQElliot't, Snyder, N.Y.",'assignor to a. I. du Pont de-Nemonrs & Company, Wilmington, Del., acorporation of Delaware No Drawing. Application March 8,,l9-t0,

Serial No. 322,991 i @Claims. (Cl. lei-142M This invention relates tothe treatment ottobacon in order to improve its color and aroma.

More particularly, itrelates to the treatment of tobacco with anammoniacal solution ot-hydrogen peroxide for the purpose of bleachingthe to-- bacco and improving its quality, which treatment is carried outby spraying on the tobacco a cooled ammoniacal solution of hydrogenperoxide.

In the past it has been proposed to treat tobacco' with solutions ofhydrogen peroxide by spraying the tobacco leaves with a'solution of theperoxide rendered alkaline by the presence of ammonia therein. It hasnow been found that when this ammoniacal solution or hydrogen peroxideis applied in the coldstate to the tobacco to be bleached the qualityand color of the resulting product are much improved over that oftobacco which hasbeen bleached with'ammoniacal solutions of hydrogenperoxide applied at room temperature or at temperatures more elevatedthan room temperature.

Accordingly, it is an object of this invention to secure the maximumbneficiation of tobacco which is'to be subjected to, the action or. anammoniacal solution ofhydrogen peroxide by spraying on the tobacco tovbe bleached a cooled solution of the treating agent. This inventioninvolves, therefore, the use of. cooled solutions of hydrogen peroxide,solutions cooledto 10 C. or below, for the purpose or securing themaximum improvement in the tobacco treated with these solutions asregards the color, aroma, and taste of the resulting product.

ammoniacal solution of le -KW a t mperuall .-bleach1n8 results overdrogen peroxide solutions at room. temperature I I when theso'lution ofvhydrogen-peroxide'has been cooled only to atemperaturewithinthe range-10"toC.

In the past, wherever animoniacal solutions of hydrogen peroiddehavebeen employed, the temperature of those solutions has been at least roomtemperature C. or higher), or in many cases me ih t above roomtemperature; In the commercial bleaching oftobacco-with ammoniacalsolutions of hydrogen peroxide it had, in fact, been ordinarily supposedthat the higher the temperature of the ammoniacal solution of hydrogenperoxide applied, the more efficient were the bleaching and aromaimproving results obtained. This conclusion was based on the generalchemical knowledge that reactions between oxidizing agents andmaterials'capable of oxidation proceeded more rapidly at highertemperatures.

Surprisingly enough, I have now discovered that the cooler theammoniacal solution of hydrogen peroxide applied to the tobacco to bebleached,jthe more effective is the treatment as regards the improvementin quality or the to- I bacco. This discovery contravenes both general achemical principles and prior established practice in this industry,which had regarded a temperature of at least room temperature or, wherepossible, temperatures higher than room temperature as essential inorder to secure most satisfactory utilization of the hydrogen peroxideIor the bleaching and improvement of the-tobacco.

fated atroom tempera r .with 'an ammonia'cal solutionpr emperatureof 5C; (41?? preferable. However-.1

The ammoniacal solution of hydrogen peroxide may be cooled to atemperature oi 10 C. or below in any convenient manner. For example, thesolution may be prepared by using refrigerated water, or water cooled toa temperature as close to 0? C. as possible. After the preparation ofthe solution by the addition of the ammonia or ammonia water to thedilute solution of hydrogen peroxide,

satisfactory cooling may be secured by introducing a block of ice intothe solution, or the solution may be prepared in a tank provided withsuitable refrigeration coils. In many cases where asource of; cooledwater is available, no special cooling ,oI-the solution may benecessary, as the Solution'may h'aveait'er preparation a temperatures!10f- C." or:below;simply because 01 the low temperature of the-waterused in preparing it.

As examplesormy improved process for imprOvinithe quality 'o f,t0baccoby spraying that I tobacco with an'ammoniacal solution of hydro-j geniperoxideg which ammoniacal solution has a temperature of 10 C. orbelow, the following may be given:

Example 1 A solution was prepared by mixing pounds or commercial Volumehydrogen peroxide solution with 65 pounds of tap water having atemperature of about 15 to 20 C. Commercial hydrogen peroxide solutionsare usually sold in solutions or 100 Volume Concentration, i.- e. 1cubic centimeter of the solution measured at 20 C. will yield 100Volumes of oxygen gas measured at C. and 760 mm. mercury pressure. Asolution of 100 Volume Concentration contains 27.6% H202 by weight andsubstantially 30.0% H20: by volume. pared, containing 'equalamounts ofcommercial 100 Volume hydrogen peroxide, solution and water had an H2O:concentration by'weight of-a'pproximately 13.8%.

To the solutionof hydrogen peroxide there was then added 5 pounds ofaqua ammonia (the aqua ammonia solution having a specific gravity of0.91). This resulted inan ammoniacal solution of hydrogen peroxidehaving a pH of approximately 9.5.

The resulting solution was then cooled by the introduction of a piece ofice to a temperature- It is evident that the solution as preofsubstantially 8 C. The solution,thusc00led,

was then used to spray 500 pounds of steamed} l 2 tire spraying processrequiring approximately-f one hour. During this entire period care wasand stemmed burley fermented tobacco; the en-a taken to insure themaintenance of a temperature of approximately 8 C. in the ammonia alsolution, of hydrogen peroxide sprayed on the tobacco. In any event,during the major portion of the spraying, care was taken to insure atemperature of 10 C. or below.

1 It'may be remarked that ii. the temperature is 10 C. or below duringthe major portion of the spraying step, the temperature may safely bepermitted to go somewhat abovefthis figure especially during the latterportion of the spraying without interfering with the improved resultsobtained with my process.

The tobacco was then piled on the floor, covered with canvas, andallowed to react. After several hours, it was thoroughly dried to the:

bone-dry condition (6 to 8% moisture content) and subsequentlyremoistened prior to its utilization in the manufacture of pipetobaccoand cigarettes.

Example 2 As a comparison experiment, the same solution described inExample 1 was prepared, but the solution was not cooled to a temperaturebelow 10 C., but was utilized to spray the same burley tobacco at roomtemperature which was 20.5 C. (69 F.). No means were provided forcooling the tobacco, either before or during the spraying, so that thetemperature rose somewhat above this value during the spraying process.

After spraying, the tobacco was piled, covered with canvas, and allowedto react as in the preceding example. After several hours reaction, itwas thoroughly dried to the bone-dry state (6 to"8% moisture content)and subsequently remoistened by the addition of water, exactly as in thepreceding example.

Upon examination, thev tobacco had not been 'irnproved very much incolor and was distinctly 1 darker than the tobacco prepared inaccordance "with Examplel. Moreover, when manufactured into cigarettesand smoked,the tobacco was found to be harsh and the aroma; was muchless pleasant than that of the tobaccdprepared in accordance withExample 1. 7

It will be apparent that while if have described certain preferredembodiments of my invention,

many changes and modifications may be made thereinwithout departing fromthe spirit of the invention. It is therefore my desire that the scope ofthe invention be determined in accord- Although the original tobacco'was relatively dark in color and harsh in quality, the tobacco, at theconclusion of the bleaching step, was bleached to a very satisfactorylight color. Moreover, its quality had been much improved, the resultingproduct being mild in character and very pleasant in aroma.

ance with, the prior art and the appended claims.

l. 'A process for improving the quality of tobacco which comprisesspraying said tobacco with an ammoniacal solution of hydrogen peroxidemaintained, during the major portion 0! the spraying process, at atemperature below 10 C.

2. A process for improving the quality of tobacco which comprisesspraying said tobacco with an ammoniacal solution of hydrogen peroxide'maintained, during the major portion of the spraying process, at atemperature below 5 C.

RALPH B. ELLIOTT.

